Insulation-stripping tools are known, e.g. from U.S. Pat. No. 2,446,558, in which the cable extremity is clamped between two relatively movable jaws while a cutter head separate and remote from these jaws is rotated about the cable axis to form a circular incision in its insulation. That type of device, because of its relatively complex construction, is not suitable for incorporation into a portable appliance such as a hand tool.